The PPPoE has certain advantages of setting up NAT, IP filtering, etc.. One more advantage is you can connect this mode in always on mode as well as you an connect when you need,without turning on&off the modem.1.) provide incorrect login details in the modem. So that Internet is not connected when the modem is turned on.2) Create a new internet connection in the computer with correct login details.and you can connect/disconnect from the computer whenever you want, with modem always turned on.